I hope he sticks to this plan about the Sires. I think Castelvecchio would be a great chance in it and the Champagne Stakes.
Many a horse has been brought undone by owners/trainers going for the Slipper instead of sticking to their original plan.
Reading the trainers thoughts - "He just does everything so easily and we never push him, today he isn't even revved up for this. He has had two gallops coming into this so he isn't even cherry ripe yet."
Perhaps that is why he was so brilliant. If he was screwed down for the race he'd probably be more dour.
Is he entered in the Slipper ?
The Skyline is 3 weeks from last Saturday and 3 weeks before the Slipper. If he has an entry for the Slipper why not go this way, The Sires is 2 weeks after the Slipper and the Champagne is 2 weeks after that.
He could run in all 4 of those races without it causing too much harm. If in the Skyline he is not impressive than rule out the Slipper, but I do not think they should rule it out completely.